Need Room Variant (add in Price)

We are unable to create product (Room) variations,
Basically we need to provide “AC Room” as extra service,
While booking Regular room, if “with AC” selected for the room, we should be able to add extra price to the regular price.

(A drop-down selection “with-AC”, “No-AC”) would do,but should have different prices.
Adding the extra cost for AC-Room is also ok.

Example:
Regular room price: 1000 /Day
with AC extra cost: 500 /Day

If AC is selected Romm cost would be 1000 + 500 = 1500 / Day
If 2 days booked, price would be (1000 + 500) x 2 = 3000

We tried to add it through “Additional service” as a checkbox select for AC-Room,
But this is One-time extra cost, works for 1-day booking,
It doesn’t work when multiple days are selected for Booking.

Please help us to create Product Variant as soon as possible, where we can add AC-Service to the same room.